Train control



Jan. 14, 1930. F. L. DODGSON 1,743,810

TRAIN CONTROL' Original Filed Jan 28, 1924 2 Sheets-Shee 1 \k I WNVENTOR A 'TTORNEY Jan. 14, 1930.

I39-Cloed belowyZZ M.P.H.

F. L-. DODGSON TRAIN CONTROL Original Filed Jan. 28. 19,24 25heets-Shee2 I26- Closed Ser. 80 Emerq.

Eng. Biqke Valve 1 ATORNEY/ inflicting Patented Jan. 14, 1930 NITE,-STATES A Prion FRANK L. nonesom-ornocnnsrnn, NEW" YORK, ,AS'SIGNOR To"GENER-AL"RAILWAY SIGNAL COMPANY, or noor-rnsrnngnnw'roan- TRAIN CONTROLOriginal application filed January 28, 1924, Serial N 04 639,020,Divided and this application 'filedvoctober 2?, 192a SerialiNo. Mano.-

This invention relates to train controlsystems, and more particularly tomeans for stimulating the vigilance of the engineer and his obedience tothe wayside signals, and for penalty if the en 'ineer does not manuallyapply the brakes before the speed 01" the train is excessive.

In applying-automatic train control apparatus to railroads it isconsidered desirable to employ such apparatus as will afford anadditional safeguard over that obtainable by a careful, alert andprudent engineer rather than as a substitute for such engineer. In otherwords, it is desirable to have the safety of the traindepend on both theautomatic train control apparatus and the engineer, ratherthan eitherofthese two standing alone.

One object and feature of thepresent invention contemplates theprovision of a simpie and direct way of determining when an adequatebrake application, such as the usual service application, has beeneffected so far as manual control is concerned,it being desirable toknow if an adequ'atebrake application has been initiated and will takeplace,

because a certain amount ottime transpiresbetwcen the completion of themanual control of a brake application and the brake application itself,this determination or manifestation of the appropriate manual control ofa brake application continuing onlyso long as the manual control 18 undsturbed and is allowed, in time, to consummate the brake application. Afurther object of the present invention resides in the provision ofmeans for inflicting apenalty upon the engineer if he himself does notproperly control the train by applying the brakes when "entering adanger-zone, thispenalizing means being rendered ineffective withoutsuppressing automatic operation of a suitable auto matic brake applyingdevice when an automatic brake application is initiated after a manualbrake applicationhas beeninitiated. Other objects, purposes andcharacteristic features of the invention will appear as the descriptionthereof progresses.

This application is a division of my prior application, Serial No.689,020, filed January lar block to which thepresent train controlapparatus is applied being illustrated;

-Fig.- 2 illustrates in a diagrammatic and conventional manner thecar-carried equipmentof the traincontrol system just referred to. v

The specific embodiments of the'invention as illustrated in the drawingsconsist of a .novelarrangement for. penalizing the engineer-lf-he doesnot attend to his duty as applied to train controlsystem of thecontinuous inductivetype.

Tmckway apparatus j oi'ntsQ into blocks in'the usual manner, only theblock '1 and the adjacent ends. of two other'blocirs Hand J being shown.Since the varicusblocks are the same, like'parts of 'eachblock havebeenidesigna'ted by like reference characters havingdistinctiveexponents. Although the trainv control system embodying the presentinvention may be used in connect on with wayside signals of any type,-.such. as semaphore signals, position light signals and color lightsignals, ithas fOPCOIlVGIllBDCQ been shown applied to a system employingsemaphore signals Z, which havebeen shown conventionally withoutilflust'ratingany particular form of their wellknown control circuitsnism.

Each of the blocks is, provided with a suitable source of alternatingcurrent energy at and control mechatheeXit end-thereof, illustrated as atrack transformer 3, and asuitable track relay t at its entrance end.This forms the welllmown closed track circuit which needs nofurthendiscussion. r

In addition to the usual track circuit curprovided.

rent flowing in the rails of a block, there is provided a circuit topermit the flow of alternating current in the two rails in multiple inthe same direction, which for convenicnce will hereinafter be referredto as the simplex circuit. In order to permit the flow of current inthis simplex'circuit, including in multiple the rails of a portion of ablock or the rails of the entire block, three balancing resistances 5, 6and 7 are bridged across the rails at the entrance, at an intermediatepoint, and at the exit end of each block respectively. In order tosupply alternating current energy to these two circuits, a transmissionline including wires 8 is strung along the track, the energy for thesimplex circuit of each block being supplied by the transformer 9;

In order to cause the simplex current to flow in one particulardirection as compared with the direction of flow of the loop circuit ortrack circuit current along the entire length of the block at one time,and cause it to flow in the opposite direction through a portion of theblock only at other times, front contacts, as 12 and 13 operated by thetrack relay of the block next in advance, as 1 are Referring to theblock 1, by looking at the circuits governed by these two front contacts12 and 13 it is readily apparent that if the track relay 4 is in itsnormal energized condition, current is permitted to flow through the tworails in multiple in the block 1 from the middle point of the balancingresistance 7 to the middle point of the balancing resistance 5, and thatwhen this track relay 4 is de-energized, current will flow in a reverserelative direction from the middle point of the balancing resistance 5through the two rails in multiple to the middle pointof the balancingresistance 6 located at an intermediate point in the block. In practicethe constants of these simplex circuits with respect to the constants ofthe loop circuit including the track transformer are so chosen that thephase displacement between these two currents is as large as possible orpractical, so that if these currents are detected by suitable apparatuson the train, that is, amplified and applied to a two element orthree-position relay, this relay produces a torque in one directionorthe other depending on the phase relation between these two currentsand in turn on the position of contacts 12 and 13 of the track relayahead.

Influence communicating means.-On the vehicle, which has beenconventionally shown by axles 15 and wheels 16, is a pair of loop ortrack circuit influence receiving elements LE, comprising cores 17terminating in pole pieces 18, each having a winding or coil 19 thereon.The coils 19 are connected in series in a manner so that the voltagesinduced therein, due to currents flowing in opposite directions in thetwo rails, are cumulative and these coils are connected to a suitableamplifying device AL (not shown in detail) which comprises thermionic orvacuum tube amplifiers of well-known commercial or special construction.The output lead wires of this amplifying device AL are connected to thewinding LR of the control relay R.

At a suitable point on the railway vehicle is a simplex element SE,which comprises a long core 20 terminating in enlarged pole pieces 21and having a coil 22 thereon for detecting the flow of simplex currentin the two rails in multiple. This coil 22 is connected to the inputside of a similar amplifying device AS which has its output terminalsconnected to the other winding SR of the control relay R. It is thusapparent that, with currents flowing in the loop circuit ahead of thetrain and in the simplex circuit under the train and having a certainphase displacement, currents will be supplied by the two amplifyingdevices AL and AS of a similar phase relation and will cause the relay Rto be operated in a certain direction, and that, if one of the trackcurrents has its relative current flow reversed, the control relay Rwill be operated in the opposite direction; and that, if one of thesecurrents is eliminated or absent, the relay R will assume itsdeenergized or biased position. This relay R is of a suitablethree-position biased type, and provided with contacts 28 and-29, whichcontrol the high cam starter magnet CSH and the low cam starter magnetCSL of a suitable speed restricting apparatus to be describedhereinafter, the currents for energizing these two magnets being derivedfrom a suitable source of energy such as a battery. The battery is notshown, but B designates a connection to one terminal, and C a connectionto the other terminal.

Train performance speed characteristics. Directly over the block I ofthe trackway shown has been illustrated a solid line curve 23 whichshows the permissive speeds at which the train may run without exceedingthe speed limit set up by the car-carried apparatus to be describedhereinafter. It will be noted that this curve has a droopingcharacteristic in the first part of the block I, continues as a straightline corresponding to a constant speed for a distance, and then againdroops until it reaches a low constant speed limit of 20 miles per hour.This first droop in the curve is caused by the high cam to be describedhereinafter, and the second droop in the curve is due to the low cam.The particular block I in connection with which these curves have beenshown is assumed to be either a down-grade block or a block in which thebraking ability of the train is poor for some other reason, and therefore requires a longer distance of movement to reduce the speed of thetrain to a certain value than the distance in which one or the other'ofthese cams run from a maximum to a minimum speed position.-

The dot-and-dash line 24 illustrated shows the speeds of the trainatdifferent' points along the track if the brakes are applied when thetrain enters the block I at a speed of about 65 miles per hour. It isthus noted that, with the character of block assumed, even though theengineer does apply the brakes upon entering the block I, he will beunable to stay below the permissive speed line set up by the high cam,this beingshown by the fact that the dot-and-dash performance curve 24crosses solid permissive speed curve 23 at the point 25. Also, if theengineer releases the brakes when he gets below the 40 miles per hourlimit, and proceeds at a constant speed until he reaches the point X inthe block, he will not be able to stay below'the permissive speed curveenforced by the low cam, even though he applies the brakes when passingthe point X, as illustrated by the fact that the dot-and-dashperformance curve 24.

crosses the solid permissive speed curve 23 at the point 26. Thecontinuation of the first droop in the 'dot-and-dash line24 has beenshown bya dotted line 27 which illustrates the speed at the variouspoints in the block that the train assumes 'if-the brake application iscontinued, that is, shows-the brake performance curve for a completestop fromhigh speed. It should be understood that the particularspeed-distance curves illustrated apply onlyto the particular set ofconditions which have been assumed in order to bring out certainadvantageous features of the present invention and that these curves arenot necessarily characteristic of train performances for all'trains inall blocks or portions of the railroad. The speed-distance curves ofpermissive speed and train performances are merely typical and are notintended to be accurately shown, being susceptible of wide variation inpractice to con 1 form with the different speed limits required fordifferent kinds of equipment and varying practices on railroads.

Uar-cawe'ed apparatus of Fig. 2Pe1rn-issioe and actual speedmeckam'sm.+Sinoe the high cam and low cam operating mechanisms aresubstantially the same, except asto theparticular shape of the cam andthe speed limit enforced, the high cam and its associated mechanism onlyhas been illustrated. The influence communicating apparatus forcontrolling both the high and the low cam ing a cam .39 fixed thereon.The arm 36 is urged upwardly by a compression spring .41, disposedaround a guide 42, so that if the cam starter magnet .CSH isde-energized the pinion 35 is urged upward into meshed relation with the mutilatedgear 37, whereupon movcment of the vehicle alongtlie track graduallyturns the cam shaft 38 and its associated cam '39. In order to returnthe shaft 38 backto its normal position in the event that the camstarting magnet CSH is again energized, a gear sector 43, aivoted at 44,engages a pinion on the camshaft 36; and this gear sector 43 is biasedto an intermediate position by initially tensioned springs 46. 1

On the shaft 30 is mounted a centrifugal speed-responsive device G ofusualand wellknown construction, which'comprises a collar 47 pinned tothe shaft 30,- and another similar but grooved collar 48 slidablymounted on this shaft, these collars being coupled together by links 49having a weight 50 at their pivotal junction, and a compression coilspring '51 between these collars.

Parallel and preferably adjacent to the shaft 38 is a speed shaft 53 towhich is pinned a bifurcated arm54 engaging the groove in the collar 48.Pinned to this shaft 53 is a speed arm 55 and speed cams 56 and 76. Anincrease in the speed ofthe shaft 30 causes the collar 48to move inresponse to the centrifugal force acting on the weights 50 in oppositiontothe spring 51, so that the speed shaft 53 and speed arm 55 and thespeed cams '56 and 7 6 are moved in a clockwise direction. To. the lowerand free end of the speed arm 55 is pivotally secured one end of afloating lever 57 which carries a roller at its other end engaging thecamsurface of the cam 39. At an intermediate point on thefioating lever5? is pivotally secured one end of a'link58 which has its otherendpivotally secured to an eccentrically located pin on the sector 59,which sector is pivotally supported on a pin 60. Adjacent the sector 59is secured a spring finger 61 which has a roller 62 pivotally securedthereto which rides on the cam surface of the sector 59. This springlinger 61 normally cooperates with a stationary finger 63 to control asuitable circuit more clearly described hereinafter. Adjacent to thespeedcam 56 are provided similar contacts 64and 65 which cooperate withthis cam 56. Likewise contacts 139 are provided to cooperate with thecam 7 6.

By looking at this structure it will be readily understood that thesector 59 will move in a clockwise direction in response to movement ofthe'cam 39 from its normal position.

It will also appear that this sector 59 moves in the same or clockwisedirection in response to an increase in the speed as indicated by thegovernor G, so that either an increase in speed or movement of the cam49 from its normal position tends to move the sector 59 in the samedirection and eventually allows the roller 62 to ride into thecontracted or reduced portion of this sector, thereby opening thecontacts 6163. In other words, after the cam 39 moves from its normalposition, the speed of the train must be correspondingly reduced toavoid opening of these contacts. Also, it will be noted that decreasingthe speed of the train to a certain value, assumed to be two miles perhour, causes the cam 56 to close a circuit at the contacts 64 and 65 andthe contacts 139 are adapted to be closed by the cam 76 when the speedof the train is below 22 miles per hour, all for reasons more clearlydescribed hereinafter.

Brake applying de'viea' The present train control system assumes theprovision of means to automatically apply the brakes of the train undercertain conditions of the carcarried apparatus. In order to accomplishsuch a brake application, a brake applying device has been illustratedconventionally by the electro-pneumatic valve EPV. This device EPV mayvent the brake pipe directly,

tion of this apparatus is deemed unnecessary.

This electro-pneumatic valve EPV is provided with contacts 104 and 188for the purposes explained hereinafter.

The usual engineers brake valve has been shown conventionally, and-isprovided with a handle 66 and with a suitable contact sector 67 which isadapted to close a circuit when this valve is in the service andemergency positions.

0 pemtion.

Normal clear 00nde't2'0ns.-Under normal 7 clear traffic conditions boththe high and the low cam assume their highest speed position 3 whichcorresponds to the maximum permissumed to be as shown by the positionsof the various devices in Fig. 2 of the drawings, the electro-pneumaticvalve EPV is energized by a stick circuit which may be traced as follows:Beginning at the terminal B of a suitable source of energy, wire 100,contacts 61 and 63," wire 101, winding of the EPV, wires 102 and 103,front contact 104 of the EPV, wire 105, back to common return wire 0.

This circuit maintains the valve EPV in its normal inactive position,allowing the train to proceed in accordance with the manner in which itis governed by the engineer.

If the engineer should allow the speed of the train to exceed themaximum limit of 65 miles per hour, the action of the governor Grclosing a pick-up circuit for the EPV, comprising wire 100, contacts 61and 63, wire 101, winding of the EPV, wires 102, 106 and 106, contacts65 and 64, wire 107, back to common return wire C. The completion ofthis circuit again picks up the EPV and this permits the engineer torelease the brakes manually if he so desires. This requirement ofbringing the speed down to practically a stop after exceeding themaximum speed limit, before the brakes can be released, is considered tobe a penalty, and is assumed to make him more vigilant in the control ofthe train tcli avoid such a brake application and pena ty.

The penalty above described for exceeding the maximum speed limit isoptional; and if desired, by a rearrangement of the circuits which willbe very evident, this penalty may be omitted so far as the maximum speedlimit is concerned, by making the electro-pneumatic valve EPV non-stickfor clear traffic conditions only by simply providing a shunt for itsfront contacts 104 closed so long as the main car relay or the high camstarter magnet CSH is energized. In fact, to conform with therequirements of some railroads, it

may be found expedient to omit the maximum I speed limit under cleartraflic conditions altogether, permitting the train to run, so far asautomatic control is concerned, at any suitable speed under cleartraflic conditions.

Caution eondz'tz'ontspeecl not excessive) Let us assume that a trainequipped with the car-carried apparatus shown in Figs. 1 and 2 is movingin the block H in the normal direction of traflic as indicated by thearrow, and that the block J is occupied by another train. With the blockJ occupied, the track relay 4 is de-energized, thereby causing thesimplex circuit between the entrance to the block I and the point X tobe reversed. Consequently, when the following train in question entersthe block I, the control relay R will swing to the reverse position,thereby dc-energizing the high cam starter magnet CSH, but maintainingthe cam starter magnet CSL energized. The high cam 39 is thus initiatedand is gradually rotatedin one direction or the other, depending onwhether the train is running pilot or tender first, thereby graduallyreducing the permissive speed, as indicated by the curve 23 in Fig. 1.If the actual speed of the train does not exceed the permissive speedlimits at any point, no automatic brake application will take eifect, itbeing'assumed for the present that the permissive speed limdoesnot'allow the speed of the train to exceed at any point these permissivespeed limits, no automatic brake application takes efiect.

Caution condte'on5'peed ewcessive.The

gradually decreasing permissive speed limits,

indicated by the curves 23 and the solid lines in Fig. l, are producedby movement of the two cams and since these cams are driven 1 V from thecar wheels, the curves of permissive speed set upare the same for eachblock or control point on the railroad, whether on an up-grade or on adown-grade; and these permissive speed curves 'are the same for theparticular lOCOIDOtlVQGLlUlPPBCl whether running alone or pulling a longor a short train.

' As previously explained, there-sometimes are permissive speedlimits'arbitrarily and auto- -matically established, 1t being assumedthat portions of track where it is not possible for all trains to keepbelow'the permissive speed limits at all points in a cautionblock,'u1'1less the train is handled and braked in some unusual orpeculiar manner.

'In conformity with the theory of traincontrol on which this inventionis based, it is desired to stimulate and enforce vigilance on the partof the engineer in obeying the indications of theblocksignals,-particulai'ly the caution signal. One Way ofmaintainingeach time heallows his train to exceed'the the engineer, in order toavoid" such penalty will keep vigilant and handle his train safely.

Such an ex edient for maintainin vi ilance i b b is found objectionablein many instanceabecause it is difficult for the engineer to observe thearbitrary speed limits for all blockswithout special manipulation.Qbviously any penalty imposed should -be one fa r'to the engineer andpreferably one whichthe engineer can readily avoid i by exercisingordinary prudence and care in the handling of the In view oftheseconsiderations, itisproposed in the present invention to provide aI penalty which the engineer may avoid in either of two ways, namely,maintaining the speediof his train at all'timesbelow'the arbitrary speedlimits, or prior to exceeding such arbitrary speed limit, manifestinghis vigilance by initiating a brake application. It is thought thatlwithsuch'arrangement the eng'ineer may handle his trainin theregularresponding control point, at which the cam is started, will not maintainthe 's'peed' of the train below the permissive speed limits, if the'train'enters the blockat its "normal running maximum speed, let usassume a train, running its normal speed of about 62' miles per hour;enters the block'l, and suppose for the first' set of conditionstliatt-he engineer is asleep, negle'ctful, or'otherw'ise fails to takeappropriateaction in obedience to the caution signal. As the traincontinues at themaXr mum speed limit prescribed by the cam, the speed'distance contacts 6163 open, and deenergize the electro-pneumatic valve5 and since thi's'va'lve is energized bya stick circuit, once 'deenergized, it remains tie-energized until picked; up by closure ofcontacts 6 l.65 at a speed of 2 m'i'les'per hour, or substantiallyproceed. This constitutes the; penalty for lack of "vigilance.

Suppose, howeverfthat the engineer sees and recognizes the cautionindlcationof the g block signal" at the entrance to the block I, suchvigilance is to penalize the engineer and.rea'liZingthe'high speed atwhich his train is'traveling,- moves the handle of his regular engineersbrake valve to the service .p'ositionfor the purpose of applying thebrakes, this. movement of the brake valve occurring before the;permissive speed limits are exceeded. sd long at the engineers brakevalve is in, the service position, it is obvious that the brakesarebeing'applied at the service rate asrapidly' as consistent withsafety and slewdo-w'n' the trainas'effectively as anautoniat'iciapplication'of the brakes. The engineerhas nuanifested inthis'vvay his vigilance, and the penalty may be suppressed. It is notnecessary in' the interests of safety to have thebrakes fully applied atthe instant the permissive speed limits are exceeded, since thesepermissive speed limits are selected and set up on the assumption thatthe starting of abrake application at that particular point and speedwill bring the train to a stop at the desired point. Accordingly, it issufficient if the engineer gets his brake valve in the service positionbefore exceeding the speed limits, the time taken to get the brakesfully applied being no longer than that required for an automaticapplication, and due allowance for this time is made in determining thepermissive speed limits.

Applying these principles to the specific system shown, wherein it isdeemed practical to require the engineer to maintain the engineers brakevalve in the service position as long as the speed of the train isexcessive, a penalty suppressing relay PR has been provided which makesit possible for the engineer to suppress or avoid the penalty providedhe moves his brake valve to the service position before an automaticbrake application is initiated and keeps it there.

Assume that the permissive speed is gradually decreasing and the speedof the train is such that it is just about to exceed the permissivespeed limit. If now the engineer moves his valve to the service oremergency position before the device EPV is de-energized, a pick-upcircuit for the penalty suppressing relay PR is completed which may betraced as follows :-beginning at the terminal B of a battery, wire 137,front contact 138 of the device EPV, wires 140 and 141, winding of thepenalty suppressingrelay PR, wire 142, contacts 126127, wire 143, backto the common return wire C. With this circuit completed the relay PRpicks up and completes a stick circuit through its front contact 144which may be traced as follows beginning at the terminal B, wire 145,front contact 144, wires 146 and 141, winding of the relay PR, wire 142,contacts 126-127, wire 143, back to the common return wire C.

If now the speed of the train exceeds the permissive speed set up by thecam 39, an automatic brake application will be initiated by the deviceEPV. This application may however beineffectual since the equalizingreservoir has alreadybeen partially vented by manual movement of thebrake valve to the service position. Even though the device EPV hasassumed its de-energized position and has opened contacts 138, thepenalty suppressing relay PR is nevertheless maintained energizedthrough its stick circuit including contacts 144, so long as theengineers valve is kept in the service P08111011; As soon as the trainspeed has been reduced to 22 miles per hour, contacts 139 are closed andthe device EPV is picked up through the following circuit :--beginningat the terminal B,

wire 100, contacts 61 and 63, wire 101, winding of the device EPV, wires102-106 and 147, contacts 139, wire 148, contact 149, wire 150, back tocommonreturn wire C. After the device EPV is once picked up, it willagain be stuck up through its stick circuit including contact 104, solong as the permissive speed set up by the cam is not exceeded.

Had the engineer put his brake valve in the service position after thebrake applying device EPV was de-energized in response to excessivespeed, the penalty suppressing relay PR- could not have been picked up,because the pick-up circuit including the contacts 138 was not intact,and consequently a penalty would have been inflicted requiring theengineer to reduce the speed to not more than 2 miles per hour beforethe device EPV could have again been picked up. Reducing the speed to 2miles per hour causes closing of contacts 64 and 65 and energization ofthis device EPV. In other words, in this arrangement the engineer, ifalert, may anticipate the automatic action by a partial or completebrought down to a low speed, assumed to be 22 miles per hour. Keepingthe brake valve in the service position for an extended period of timemay result in an unnecessary reduction in brake pipe pressure; but insome cases and under some circumstances, this may not be objectionable,thetrain frequently being braked down to a speed less than a suitablecontrol speed, such as 22 miles per hour, before the brake pipe has beenmaterially over reduced.

Danger condz'tz'om-W'hen the train enters the block J assumed to beoccupied by another train, the loop circuit influence receiving coils 19will be deprived of trackway energy and the control relay R will assumeits de-energized position regardless of whether or not simplex circuitcurrent is flowing in the block J, because the track or loop circuitcurrent is shunted away from the train in question by reason of thetrain ahead. Assume now that, with the train in question moving in theblock J, the other train heretofore mentioned moved out of the block Jinto the following block. Under this condition the loop circuitapparatus of the train in question again receives energy from the loopcircuit ahead of the train, and the simplex Winding of the relay R acurrent of reversed'relative direction of flow therein, so that therelay Ragain assumes the reversed position and permits the train toproceed at an intermediate speed of d0 miles per hour, for example, asindicated in the diagram, in Fig. 1, provided the train in question isto the rear of the point X for the block J. It is thus noted that thetrain control apparatus may be released of its restricting control at anintermediate point in a danger block as soon as track conditions aheadbecome favorable, this also being true when a train moves in a cautionblock and such block clears up in the meantime.

In the specific form of the invention shown and described the primarypurpose is to stimulate and maintain vigilance on the part of theengineer, requiring him, under penalty of being obliged to come topractically a full stop instead of being restricted to a limited speed,and to recognize and observe the indications of the block signals,particularly the caution signal. Further, the engineer is penalized ifhe does not control his train properly and in accordance with theindications of the wayside signals, and means is also provided forsuppressing the penalty ordinarily inflicted upon the engineer providedhe has initiated a manual application of the brakes before an automaticbrake application has been initiated, this penalty suppressing meansrequiring the engineer to keep his brake valve in the service positionpermanently until the speed of the train has been reduced to a safevalue, which has been taken at 22-miles per hour.

Having thus shown and described one specific embodiment of the inventionas applied to continuous inductive train, control systems, the specificdisclosure made has been shown to illustrate the motive of the inventionrather than its scope, and it is desired'to be understood that variouschanges and modifications may be made to adapt the invention to othertypes of systems without departing from the spirit of the invention orthe idea of means underlying the same.

'lVhat I claim is 1. An automatic train control system comprising, abrake control device, means for automatically actuating said brakecontrol device, means infiict-ing a penalty each time the brake controldevice is actuated, and means for restoring said brake control device tonormal without inflicting said penalty, and means permitting said lastmentioned means to be made active and eifective only if the engineersbrake valve is placed in the service position and is kept in suchposition until the train speed has been reduced to a safe value.

2. An automatic train control system com-,

prising, a brake control device, a permissive peed device, an actualspeed device, means for actuating said brake control device if theactual speed exceeds the permissive speed, means for restoring saidbrake control device effective only after a penalty has been inflicted,and other means for restoring said brake control device without penaltyeffective only if the speed of the train has been reduced to a certainvalue as a result of a maintained manual application of the brakesinitiated prior to the automatic actuation of said brake control device.

3. An automatic train control system, comprising a brake controldevice,a permissive speed device, an actual speed device, means for actuatingsaid brake control device if the actual speed exceeds the permissivespeed, means for restoring said brake control device eifective onlyafter a penalty'has been inflicted, and other means for restoring saidbrakecontrol effective if and only if the e11 gineers brake valve hasbeen placed in the service or emergency position before said brakecontrol device was actuated and has been kept there until the speed ofthe train is no longer excessive.

4. An automatic train control system comprising, a brake control device,a permissive speed device, an actual speed device, means for actuatingsaid brakecontrol device if the actual speed exceeds the permissivespeed, means for restoring said brake controldevice effective only'aftera penalty has been inflicted, and another. means for restoring saidbrake control device to normal effective if and only if the engineer hasplaced the brake valve in a brake applying position before the brakecontrol device was actuated and has kept it there until a predeterminedeffect has been produced.

5. An automatic train control system comprising, a brake control device,means for automatic'ally actuating said brake control clevice, meansinflicting a penalty each time the brake control device is actuated,means for restoring said brake control device to normal withoutinflicting said penalty, and means permitting said last mentioned meansto be made active and effective only if the engineers brake valve isplaced in the brake applying position and is kept in such position untilthe train speed has been reduced to a predetermined value.

6. In an automatic train control system, in combination, a brake controldevice, an energizing circuit for said device including, on one side ofsaid device contacts controlled by a speed distance cam, and on theother side of said device a plurality of branches in multiple, onebranch including a stick contact of said device, one branch includingonly a contact closed at low vehicle speed, and one branch a contactclosed at medium vehicle speed and a front point of an acknowledgingrelay.

of said device a plurality of branches in multiple, one branch includinga stick contact of said device, one branch including only a contactclosed at low vehicle speed, and one branch a contact closed at mediumvehicle speed and a front point of an acknowledging relay, saidacknowledging relay having an energizing pick up circuit includingcontacts closed only when the engineers brake valve is in brake applyingposition.

8. In an automatic train control system, in combination, a brake controldevice, an energizing circuit for said device including, on one side ofsaid device contacts controlled by a speed distance cam, and on theother side of said device a plurality of branches in multiple, onebranch including a stick contact of said device, one branch includingonly a con tact closed at low vehicle speed, and one branch a contactclosed at medium vehicle speed and a front point of an acknowledgingrelay, said acknowledging relay having an energizing pick up circuitincluding contacts closed only when the engineer brake valve is in brakeapplying position, and a stick circuit for said acknowledging relayincluding the last saidicontacts.

In testimony whereof I hereby affix my signature.

FRANK L. DODGSON.

